Presently, a building with multi-zone electrical heat includes zones with one or more heating units (resistive electric baseboard or forced air heaters) which are each controlled by a single thermostat. The thermostats are typically of the type which have circuitry for switching the heating units ON and OFF based upon a comparison between a temperature setpoint value and the temperature monitored within the respective zone. In particular, the thermostats may use mechanical or electrical components and configurations to compare the setpoint and actual temperatures, and switch the heating units ON and OFF based upon the comparison.
Setback thermostats have become commonly used in buildings heated by a single heating unit (central furnace) for the purpose of conserving energy; however, the added cost of these thermostats prevents them from being cost effective for certain buildings having multi-zone electrical heat, and multiple thermostats. Additionally, even if setback thermostats where installed in every zone, it would be a burdensome task to maintain and revise all of the setback values for every thermostat. For example, for a building such as a home with ten rooms each controlled as separate zones by setback thermostats and each having 4 temperature settings for each day of the week, the user would be required to initially set and maintain 28 settings at 10 locations for a total of 280 settings.
Accordingly, it would be desirable to provide a central controller for storing and updating temperatures while also providing local temperature sensing and selectable temperature control. However, existing buildings are presently the largest market for installing such systems with central control, and, as is known, existing buildings, such as homes, generally are difficult to wire for communication links such as those required between a central controller and thermostats for each zone. Thus, it would also be desirable to provide a central controller and multiple thermostats which communicate using a medium which does not require the installation of wiring.